On treating a compound with warm dil. $$H_2SO_4$$, gas X is evolved which turns $$K_2Cr_2O_7$$ paper acidified with dil. $$H_2SO_4$$ to a green compound Y. X and Y respectively are:

A

$$X = SO_2, Y = Cr_2O_3$$

B

$$X = SO_2, Y = Cr_2(SO_4)_3$$

C

$$X = SO_3, Y = Cr_2(SO_4)_3$$

D

$$X = SO_3, Y = Cr_2O_3$$